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xaco
09-21-2010, 04:33 PM
hi everyone,i downloaded MadCAM demo and it looks great but i have a problem how to get a 3D toolpath that would show cutters tip,and not cutters centre.When i go to settings "2d options"->"2D milling" and i set "cutter tip",the next toolpath continues to show the centre of cutter .:confused:how can i get right toolpath? thx

turmite
09-22-2010, 04:01 PM
xaco can you post the 3dm file so I can test it? I just tested on one of my models here and got exactly what I was supposed to.

I am curious if you are using a ball nose cutter? Give me some more info so maybe I can help.

Mike

xaco
09-22-2010, 05:30 PM
Mike,i cant post(attach) file-its "invalid" if 3dm,and "problem with page" if dxf....,i am testing madcam so i made simplest surface of revolved curve around x-axis.I made a circle above it and i made vertical projection on that surface to gain a projected curve that i wanted to mill,just that piece,selecting "set 3 axis mode" and than "Curve Milling->From Boundary Curves"and i selected that projected curve.I get toolpath that shows center of tool when i pick ball end mill,bigger diameter,higher toolpath.If i choose flat end mill i get normal toolpath.

turmite
09-22-2010, 05:46 PM
xaco are you wanting to only carve the curve, or remove the material inside the curve?

Mike

turmite
09-22-2010, 06:01 PM
xaco did you try to simulate the tool path?

xaco
09-22-2010, 06:08 PM
xaco did you try to simulate the tool path?

yes i did,and simulation clearly shows that toolpath is higher than material where was cut out.Yes i want to remove all material out,not cut along line.

turmite
09-22-2010, 06:24 PM
xaco here is a screen shot showing the tool path I got using a 6mm ballnose, used curve milling and from boundry curves. Rhino will always select the center of the ball for this tool path and will show the path to be above the surface, but the depth of cut will be half the ball diam into the surface.

Mike

turmite
09-22-2010, 06:26 PM
Xaco I should say as well that the cut will follow the contour of the part and if you study the pic you will see it in the image.

Let me know if you have other questions.

Mike

xaco
09-22-2010, 06:53 PM
Xaco I should say as well that the cut will follow the contour of the part and if you study the pic you will see it in the image.

Let me know if you have other questions.

Mike

So its always in center when using ballmill.Anyway its ok cos in mach3 it shows the toolpath of the tip so g-code is of tip toolpath.

turmite
09-22-2010, 08:49 PM
Xaco,

No not always centered. It depends on which strategy you are using and what options are available for those strategies.

If I can be of futher help, let me know.

Mike

svenakela
09-23-2010, 04:09 AM
[Deleted text]

Ooops, posted in wrong thread. :)

JOM
09-24-2010, 04:29 AM
Xaco,

Each toolpath curve is always saved in Rhino at cutter center, but you can choose cutter tip or cutter center for the output by setting a parameter in the post processor. The default setting for the output is cutter tip.

Joakim

Dan B
09-24-2010, 05:20 PM
Displaying toolpaths from the tool center is the right way to do it, in my opinion. If the toolpaths were displayed from the tool tip, you would never catch it if you program with an endmill but intended to use a ballcutter, or vise versa. Also, just picture a toolpath displayed from the tooltip using a ballnose cutter and cutting an arc in the Z axis. The tool contact point changes, so the cutter path wouldn't look right. The actual contact point of the tool wouldn't be the actual tip, so the display could be deceptive. Of course the display could be calculated to display correctly, but displaying from the tool center makes this unnecessary. Check out these illustrations which hopefully illustrates the potential issue.

Dan

jeangui
10-14-2013, 09:44 AM
EDIT-----
Actually, this appears to occurs when there is no bottom surface in the model. The logic will not consider the bottom surface of the box-region automatically generated in the same way as a "selected model surface".
In the earlier case, the toolpath will behave as descibed in the post below. When a bottom surface is selected as a model the toolpath will be correctly calculated to ensure that it does not undercut.

So, my learning is, make sure there is a bottom surface to ensure the correct generation of the toolpath.

Regards,
Jean P.


-------------------------
Hello All,

I have noticed that the for ball-end tools, the toolpath generated will actually undercut the model by an height equal to the radius (see picture enclosed).
I am wondering if this is the expected behavior ? Or whether it would make more sense in this case to have the option to ensure that the tool tip does not go below the bottom of either the clipping plane or the bottom of the bounding box (whatever is highest).
To work around this, I have set the the lower clipping plane to be equal to z-bottom + radius of the tool. But this is quite a manual task to do...
Any thoughts there ?

Thanks,
Jean P.


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